Breeding Green Water Dragons

By Michael Spears

After 10 years of working with the green water dragon (Physignathus cocincinus), also called the Asian water dragon, we at Sapphire Dragon Ranch know a great deal about the challenges of breeding this species in captivity. It isn’t easy; getting their eggs to hatch can be a challenge.

Arboreal Accommodations

The average adult green water dragon is 25 to 30 inches long. Females are approximately 1 to 8 inches shorter than males. The perfect setup to breed a pair of water dragons is a tall, heavy-duty soft-screen enclosure. The lizards have to be able to climb. Their muscles will atrophy in a glass enclosure that doesn’t allow them the exercise they require. No more 55-gallon glass tanks, please! Provide them with an enclosure at least 4 to 6 feet tall by 21⁄2 to 4 feet wide, and keep the setup’s length similar to its width.

Photo by Gina Cioli/I-5 Studio

Once green water dragons measure about 20 inches, they start breeding like crazy.

We use cypress mulch for the substrate and plastic shoeboxes for bathing dishes. They measure approximately 15 inches long by 8 inches wide by 4 inches deep. Water is changed every other day. Keep the temperature under the hotspot between 80 and 85 degrees Fahrenheit, and the cool end between 67 and 70 degrees.

Green water dragons love to eat insects, but feeding them too many can cause liver failure, so go easy on them. Balancing bearded dragon pellets, sweet fruit and insects works best. We keep a small dish of pellets always present and then feed the lizards about 10 crickets a week. Soft fruits, such as white grapes and soft pears, are offered three times a week.

Most commercially available pellets supply all the vitamins and minerals in a balanced form, so we don’t use ultraviolet lighting with our dragons. In our experience, the lizards don’t like direct sun exposure. They become stressed out, especially when they don’t have a place to hide from it, and display behaviors such as turning their backs and biting their keepers’ fingers. They don’t mind a mild ultraviolet bulb, but avoid high-output mercury vapor bulbs that emit ultraviolet light because those can burn their skin.

Finding the Right Mates

Finding an adult male and female sounds easy, but often you are at the mercy of the people sexing them. Some can actually do it, and others just want to take your money. Visually, you can tell green water dragons apart by a few characteristics. Males usually show a high rooster comb on the back of their necks once they’re 6 months old. Females have a small rooster comb, which gives males something to hold during copulation. If you are buying hatchlings at the local pet store, purchase at least three, and hope you get a male and a female to pair together. Females often start fighting with each other when they reach 2 to 4 months old.

Breeding Frenzy

Once green water dragons measure about 20 inches, they start breeding like crazy. Breeding season occurs in late fall and winter. Dragons get approximately 12 to 14 hours of light a day. We have never had any need to adjust the photoperiod.

In our enclosures we provide one male with two females to ensure that the eggs each female lays are fertile. We always keep these groups together because we never know when the dragons will mate.

Breeding is often a violent affair. The male picks whichever female is closest, grabs her by the neck and drags her to wherever he feels most comfortable to mount her. This activity can happen several times.

About 21 days later the fertilized female starts scratching about the cage looking for a suitable egg-laying site. We use a deep plastic container measuring 10 inches wide by 18 inches long by 18 inches tall as an egg-laying box, fill it with damp sphagnum moss, and place it in the cool area of the enclosure away from the water dish.

A gravid female placed in this box may jump back out, but when she is ready, she will return and start digging in a corner to lay her eggs. Over the course of two hours she will deposit anywhere from seven to 15 eggs on average. She then covers them, packs the dirt and moss with her nose, and actually digs a decoy hole on the other side of the box to fool predators.

Incubation Tips

Once a female green water dragon has deposited her eggs, carefully dig them up. Make sure to keep them facing the same side up that you found them. Failing to do so can deprive hatchlings of oxygen and suffocate them.

Note that females are famous for laying infertile eggs. This can happen with or without the presence of a male dragon. Bad eggs usually turn yellow in about two to three weeks. Good eggs are plump and white. Holding a flashlight up to them reveals small red veins inside.

In a plastic shoebox place all fertile eggs in rows of four or five atop 1 inch of damp vermiculite or perlite. Cover the shoebox with a top that has one hole measuring approximately one-eighth inch wide on each corner to provide ventilation. Place the box in an incubator, and set the temperature at 84 to 86 degrees.

Check eggs every two weeks to make sure they’re not drying out or turning yellow. Throw out the bad ones, which have turned yellow or have mold on them. As the weeks progress, the grape-sized eggs grow to almost a pecan size. They hatch within 60 days.

Hatchling TLC

After hatchlings emerge from their eggs, soak them overnight in a plastic container with warm, shallow water below their noses. Once this soak is complete, move them into a 20-gallon tank with a screen top. Position a small 75-watt heat lamp on one side of the enclosure, and use a timer to provide a 12-hour photoperiod. Give hatchlings the same temperatures as the adults. Place small plants within their enclosure to give them places to hide behind.

Feed them two to three pinhead crickets a day, and dust the food offering with vitamin and mineral powder twice a week. Once the lizards reach 4 weeks old, add a bowl of small beardie pellets to the enclosure. Mist green water dragons twice a day, and provide a water dish for bathing. Of course, make sure the dish is not so deep that they may drown. Placing a rock or branch within it usually helps to prevent this.

After three weeks, move the lizards into screen cages of at least 30 gallons. Dragons can be set up in groups of four or five at this point. Adjust food to include slightly larger crickets and one-eighth-inch pellets. As the lizards get bigger their cages should get bigger.

Green water dragons are a lot of work to breed in comparison to other dragons and geckos out there, but if you can raise these guys, you can succeed with anything. They are definitely worth the trouble.